These were the last words from the missing Malaysia Airlines flight MH370, revealed for the first time at a meeting in Beijing on Wednesday between the Malaysian government and Chinese relatives.

The flight then disappeared from radar screens, according to Malaysia's civil aviation officials at the meeting fronted by its envoy to China, Datuk Iskandar Sarudin, and held in a packed room with nearly 400 relatives at the Metropark Lido hotel.

Five days after the plane vanished above the South China Sea authorities in Kuala Lumpur have also revealed a military radar may have recorded the aircraft several hundred kilometres off course in the Malacca Strait.

But Air Force Chief Rodzali Daud told reporters that experts were still analysing the data.

''It is difficult to say for sure if it is the aircraft,'' he said.

Military radar picked up a radar ''plot'' 200 miles north-west of the Malaysian island of Penang at 2.15am last Saturday, about an hour after flight 370 disappeared from civilian aviation radar 120 miles from the Malaysia coast en-route to Vietnam.

Malaysian authorities are now focusing a massive search operation on the Malacca Strait.

But the search will also continue in the South China Sea while doubts remain whether the military radar recorded flight 370 or another aircraft.

The air force's revelation has deepened the mystery of one the world's worst aviation disasters.

There is no explanation how the plane could have turned back and flown over mainland Malaysia without being recorded on radar or by other sources.

Malaysian authorities admit they are unsure what direction Malaysia Airlines flight 370 was flying when the plane carrying 239 people disappeared from radar over the South China Sea.

The massive search has been expanded to several hundred kilometres as it emerged the US airline safety regulator had issued a warning in February of cracking in the fuselage skin underneath a Boeing 777's satellite antenna. The flaw could lead to the airliner breaking up or rapid decompression.

Malaysia's civil aviation chief Azharuddin Abdul Rahman confirmed it was possible the Boeing 777 turned back two hours into the six-hour flight. ''We are still investigating and looking at the radar readings,'' he said.

The problem with 777's satellite antenna was identified by the US Federal Aviation Administration last June but the Air Directive telling airlines to inspect this part of the plane for cracks was not issued by the FAA until February 18.

The 777-200 ER, the model operating flight MH370, was not specifically identified in the directive.

According to a Malaysia Airlines spokesman, the missing aircraft was serviced on February 23, with further maintenance scheduled for June 19. It is not known whether the airline picked up the directive.

A structural failure related to the flaw could disable satellite communications, including the Aircraft Communications Addressing and Reporting System, which transmits data of the plane's location automatically, the directive warns.

It would also have rendered the plane invisible to all but ''primary radar'', which has a range of only 100 nautical miles.

The directive also warned cracking and corrosion at this point could lead to ''rapid decompression and loss of structural integrity of the airplane''.

A posting on the Professional Pilots Rumour Network said the end of satellite communications would not have disabled the mobile phone network on the plane.

Nineteen families signed a statement saying they were able to telephone the mobile phones on the plane. While they got a ring tone, no one picked up.